Augmented reality (AR) has played prominently in nearly all of Apple's events since iOS 11 was introduced, Tim Cook has said he believes it will be as revolutionary as the smartphone itself, and AR was Apple's biggest focus in sessions with developers at WWDC this year.

But why? Most users don't think the killer app for AR has arrived yet - unless you count Pokémon Go. The use cases so far are cool, but they're not necessary and they're arguably a lot less cool on an iPhone or iPad screen than they would be if you had glasses or contacts that did the same things.

While AR clearly has a role to play in professional settings (e.g construction work, medical settings, and so on), I still haven't seen a general purpose application that justifies the heavy investment in AR by Apple. All demos usually come down to "oh, that's neat, I guess" and "that is incredibly uncomfortable". Where's the killer app?